Method of manufacturing semiconductor device, substrate processing apparatus, and recording medium

ABSTRACT

There is included (a) forming a protective film on a surface of a third base by supplying a processing gas to a substrate in which a first base containing no oxygen, a second base containing oxygen, and the third base containing no oxygen and no nitrogen are exposed on a surface of the substrate; (b) modifying a surface of the second base to be fluorine-terminated by supplying a fluorine-containing gas to the substrate after the protective film is formed on the surface of the third base; and (c) selectively forming a film on a surface of the first base by supplying a film-forming gas to the substrate after the surface of the second base is modified.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2019-140991, filed on Jul. 31, 2019, theentire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a method of manufacturing asemiconductor device, a substrate processing apparatus, and a recordingmedium.

BACKGROUND

As an example of processes of manufacturing a semiconductor device, aprocess of forming a film by selectively growing it on a surface of aspecific base among a plurality of kinds of bases exposed on a surfaceof a substrate (hereinafter, referred to as selective growth orselective film formation) is often carried out.

SUMMARY

The present disclosure provides some embodiments of a technique capableof enhancing a selectivity in the selective growth described above whilesuppressing damage to a surface of a base.

According to one or more embodiments of the present disclosure, there isprovided a technique that includes (a) forming a protective film on asurface of a third base by supplying a processing gas to a substrate inwhich a first base containing no oxygen, a second base containingoxygen, and the third base containing no oxygen and no nitrogen areexposed on a surface of the substrate; (b) modifying a surface of thesecond base to be fluorine-terminated by supplying a fluorine-containinggas to the substrate after the protective film is formed on the surfaceof the third base; and (c) selectively forming a film on a surface ofthe first base by supplying a film-forming gas to the substrate afterthe surface of the second base is modified.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the presentdisclosure.

FIG. 1 is a schematic configuration view of a vertical type processfurnace of a substrate processing apparatus suitably used in embodimentsof the present disclosure, in which a portion of a process furnace 202is shown in a vertical cross sectional view.

FIG. 2 is a schematic configuration view of a vertical type processfurnace of the substrate processing apparatus suitably used inembodiments of the present disclosure, in which a portion of the processfurnace 202 is shown in a cross sectional view taken along line A-A inFIG. 1.

FIG. 3 is a schematic configuration view of a controller 121 of thesubstrate processing apparatus suitably used in embodiments of thepresent disclosure, in which a control system of the controller 121 isshown in a block diagram.

FIG. 4 is a view illustrating a process sequence in selective growthaccording to embodiments of the present disclosure.

FIG. 5A is a partial enlarged cross sectional view of a surface of awafer 200 before a cleaning process, FIG. 5B is a partial enlarged crosssectional view of the surface of the wafer 200 after the cleaningprocess in which a base 200 a containing a silicon nitride film, a base200 b containing a silicon oxide film, and a base 200 c containingsilicon are each exposed on its surface, FIG. 5C is a partial enlargedcross sectional view of the surface of the wafer 200 after a protectivefilm 200 e is formed on a surface of the base 200 c by supplying anoxygen-containing gas, FIG. 5D is a partial enlarged cross sectionalview of the surface of the wafer 200 after silicon is selectivelyadsorbed on respective surfaces of the base 200 b and the protectivefilm 200 e by supplying an aminosilane-based gas, FIG. 5E is a partialenlarged cross sectional view of the surface of the wafer 200 after therespective surfaces of the base 200 b and the protective film 200 e, onwhich the silicon is adsorbed, are selectively modified by supplying afluorine-containing gas, FIG. 5F is a partial enlarged cross sectionalview of the surface of the wafer 200 after a silicon nitride film isselectively formed on a surface of the base 200 a, and FIG. 5G is apartial enlarged cross sectional view of the surface of the wafer 200after the wafer 200 illustrated in FIG. 5F is exposed to the atmosphere.

DETAILED DESCRIPTION

Reference will now be made in detail to various embodiments, examples ofwhich are illustrated in the accompanying drawings. In the followingdetailed description, numerous specific details are set forth in orderto provide a thorough understanding of the present disclosure. However,it will be apparent to one of ordinary skill in the art that the presentdisclosure may be practiced without these specific details. In otherinstances, well-known methods, procedures, systems, and components havenot been described in detail so as not to unnecessarily obscure aspectsof the various embodiments.

<One or more Embodiments of the Present Disclosure>

Embodiments of the present disclosure will now be described mainly withreference to FIGS. 1 to 4.

(1) Configuration of the Substrate Processing Apparatus

As illustrated in FIG. 1, a process furnace 202 includes a heater 207 asa heating mechanism (temperature adjustment part). The heater 207 has acylindrical shape and is supported by a holding plate so as to bevertically installed. The heater 207 functions as an activationmechanism (an excitation part) configured to thermally activate (excite)a gas.

A reaction tube 203 is disposed inside the heater 207 to be concentricwith the heater 207.

The reaction tube 203 is composed of a heat resistant material, e.g.,quartz (SiO₂), silicon carbide (SiC) or the like, and has a cylindricalshape with its upper end closed and its lower end opened. A manifold 209is disposed below the reaction tube 203 in a concentric relationshipwith the reaction tube 203. The manifold 209 is composed of a metalmaterial, e.g., stainless steel (SUS), and has a cylindrical shape withits upper and lower ends opened. The upper end of the manifold 209engages with the lower end of the reaction tube 203. The manifold 209 isconfigured to support the reaction tube 203. An O-ring 220 a as a sealis installed between the manifold 209 and the reaction tube 203. Similarto the heater 207, the reaction tube 203 is vertically installed. Aprocessing vessel (reaction vessel) mainly includes the reaction tube203 and the manifold 209. A process chamber 201 is formed in a hollowcylindrical portion of the processing vessel. The process chamber 201 isconfigured to accommodate wafers 200 as substrates. The process to thewafers 200 is performed in the process chamber 201.

Nozzles 249 a to 249 c as first to third supply parts are installed inthe process chamber 201 to penetrate a sidewall of the manifold 209. Thenozzles 249 a to 249 c will be referred to as first to third nozzles,respectively. The nozzles 249 a to 249 c are each composed of a heatresistant material such as quartz, SiC, or the like. Gas supply pipes232 a to 232 c are connected to the nozzles 249 a to 249 c,respectively. The nozzles 249 a to 249 c are different nozzles, in whicheach of the nozzles 249 a and 249 c is installed adjacent to the nozzle249 b.

Mass flow controllers (MFCs) 241 a to 241 c, which are flow ratecontrollers (flow rate control parts), and valves 243 a to 243 c, whichare opening/closing valves, are installed in the gas supply pipes 232 ato 232 c sequentially from the upstream sides of gas flow, respectively.Gas supply pipes 232 d to 232 h are connected to the gas supply pipes232 a to 232 c at the downstream side of the valves 243 a to 243 c,respectively. MFCs 241 d to 241 h and valves 243 d to 243 h areinstalled in the gas supply pipes 232 d to 232 h sequentially from theupstream sides of gas flow, respectively. The gas supply pipes 232 a to232 h are each composed of a metal material such as, e.g., stainlesssteel (SUS) or the like.

As illustrated in FIG. 2, the nozzles 249 a to 249 c are each disposedin a space with an annular shape in a plane view between the inner wallof the reaction tube 203 and the wafers 200 such that the nozzles 249 ato 249 c extend upward along an arrangement direction of the wafers 200from a lower portion of the inner wall of the reaction tube 203 to anupper portion of the inner wall of the reaction tube 203. Specifically,the nozzles 249 a to 249 c are installed at a lateral side of a waferarrangement region in which the wafers 200 are arranged, namely in aregion which horizontally surrounds the wafer arrangement region, toextend along the wafer arrangement region. The nozzle 249 b is disposedto face an exhaust port 231 a, which will be described later, on astraight line in a plane view, with the centers of the wafers 200carried into the process chamber 201 interposed therebetween. Thenozzles 249 a and 249 c are disposed to sandwich a straight line Lpassing through the nozzle 249 b and the center of the exhaust port 231a from both sides along the inner wall of the reaction tube 203 (theouter peripheral portion of the wafers 200). The straight line L is alsoa straight line passing through the nozzle 249 b and the centers of thewafers 200. That is, it may be said that the nozzle 249 c is installedat the opposite side of the nozzle 249 a with the straight line Linterposed therebetween. The nozzles 249 a and 249 c are disposed inline symmetry with the straight line L as a symmetry axis. Gas supplyholes 250 a to 250 c for supplying a gas are installed on the sidesurfaces of the nozzles 249 a to 249 c, respectively. The gas supplyholes 250 a to 250 c are opened to face the exhaust port 231 a in aplane view, so as to allow a gas to be supplied toward the wafers 200.The gas supply holes 250 a to 250 c may be formed in a plural numberbetween the lower portion of the reaction tube 203 and the upper portionof the reaction tube 203.

A gas, which contains silicon (Si) as a main element constituting a filmto be formed on each of the wafers 200 and a halogen element, i.e., ahalosilane-based gas, is supplied from the gas supply pipe 232 a intothe process chamber 201 via the MFC 241 a, the valve 243 a, and thenozzle 249 a. The halosilane-based gas acts as a film-forming gas, i.e.,a Si source (precursor gas). The halogen element includes chlorine (Cl),fluorine (F), bromine (Br), iodine (I), and the like. As thehalosilane-based gas, it may be possible to use, for example, achlorosilane-based gas containing Si and Cl, for example, a silicontetrachloride (SiCl₄) gas.

A fluorine (F)-containing gas is supplied from the gas supply pipe 232 binto the process chamber 201 via the MFC 241 b, the valve 243 b, and thenozzle 249 b. As the fluorine-containing gas, it may be possible to use,for example, a fluorine (F₂) gas.

A hydrogen nitride-based gas, which is a nitrogen (N)-containing gas, issupplied from the gas supply pipe 232 c into the process chamber 201 viathe MFC 241 c, the valve 243 c, and the nozzle 249 c. The hydrogennitride-based gas acts as a film-forming gas, i.e., a N source (anitriding gas or a nitriding agent). As the hydrogen nitride-based gas,it may be possible to use, for example, an ammonia (NH₃) gas.

An aminosilane-based gas, which is a gas containing Si and an aminogroup, is supplied from the gas supply pipe 232 g into the processchamber 201 via the MFC 241 g, the valve 243 g, the gas supply pipe 232c, and the nozzle 249 c.

As the aminosilane-based gas, it may be possible to use, for example, amonoaminosilane (SiH₃R) gas which is a precursor containing one aminogroup in a composition formula (in one molecule). R refers to an aminogroup in which one or two hydrocarbon groups containing one or more Catoms are coordinated to one N atom (the one in which one or both of Hof an amino group represented by NH₂ is substituted by a hydrocarbongroup containing one or more C atoms). When two hydrocarbon groups eachconstituting a portion of the amino group are coordinated to one N, thetwo hydrocarbon groups may be the same hydrocarbon group or differenthydrocarbon groups. Furthermore, the hydrocarbon group may contain anunsaturated bond such as a double bond or a triple bond. Moreover, theamino group may have a cyclic structure. Since the amino group is bondedto Si, which is the central atom of the SiH₃R molecule, this amino groupwill also be referred to as a ligand or an amino ligand.

As the SiH₃R gas, it may be possible to use, for example, anethylmethylaminosilane (SiH₃[N(CH₃)(C₂H₅)]) gas, a dimethylaminosilane(SiH₃[N(CH₃)₂]) gas, a diisopropylaminosilane (SiH₃[N(C₃H₇)₂]) gas, adisecondary butylaminosilane (SiH₃[H(C₄H₉)₂]) gas, adimethylpiperidinosilane (SiH₃[NC₅H₈(CH₃)₂]) gas, or adiethylpiperidinosilane (SiH₃[NC₅H₈(C₂H₅)₂]) gas.

An oxygen (O)-containing gas is supplied from the gas supply pipe 232 hinto the process chamber 201 via the MFC 241 h, the valve 243 h, the gassupply pipe 232 a, and the nozzle 249 a. The O-containing gas acts as aprocessing gas, i.e., an oxidizing agent. As the O-containing gas, itmay be possible to use, for example, an oxygen (O₂) gas.

An inert gas, for example, a nitrogen (N₂) gas, is supplied from the gassupply pipes 232 d to 232 f into the process chamber 201 via the MFCs241 d to 241 f, the valves 243 d to 243 f, the gas supply pipes 232 a to232 c, and the nozzles 249 a to 249 c. The N₂ gas acts as a purge gas, acarrier gas, a dilution gas, or the like.

A film-forming gas supply system (a precursor gas supply system or areaction gas supply system) mainly includes the gas supply pipes 232 aand 232 c, the MFCs 241 a and 241 c, and the valves 243 a and 243 c. Aprocessing gas supply system (an oxygen-containing gas supply system)mainly includes the gas supply pipe 232 h, the MFC 241 h, and the valve243 h. An aminosilane-based gas supply system mainly includes the gassupply pipe 232 g, the MFC 241 g, and the valve 243 g. Afluorine-containing gas supply system mainly includes the gas supplypipe 232 b, the MFC 241 b, and the valve 243 b. An inert gas supplysystem mainly includes the gas supply pipes 232 d to 232 f, the MFCs 241d to 241 f, and the valves 243 d to 243 f.

One or more of various supply systems described above may be configuredas an integrated supply system 248 in which the valves 243 a to 243 h,the MFCs 241 a to 241 h, and the like are integrated. The integratedsupply system 248 is connected to each of the gas supply pipes 232 a to243 h so that a supply operation of various kinds of gases into the gassupply pipes 232 a to 232 h, i.e., an opening/closing operation of thevalves 243 a to 243 h, a flow-rate-adjusting operation by the MFCs 241 ato 241 h or the like, is controlled by a controller 121 which will bedescribed later. The integrated supply system 248 is configured as anintegral type or division type integrated unit, and is also configuredso that it is detachable from the gas supply pipes 232 a to 232 h or thelike, so as to perform maintenance, replacement, expansion, or the likeof the integrated supply system 248, on an integrated unit basis.

The exhaust port 231 a configured to exhaust an internal atmosphere ofthe process chamber 201 is installed at a lower side of the sidewall ofthe reaction tube 203. As illustrated in FIG. 2, the exhaust port 231 ais installed at a position facing the nozzles 249 a to 249 c (the gassupply holes 250 a to 250 c) in a plane view, with the wafers 200interposed therebetween. The exhaust port 231 a may be installed betweenthe lower portion of the sidewall of the reaction tube 203 and the upperportion of the sidewall of the reaction tube 203, i.e., along the waferarrangement region. An exhaust pipe 231 is connected to the exhaust port231 a. A vacuum pump 246 as a vacuum exhaust device is connected to theexhaust pipe 231 via a pressure sensor 245 as a pressure detector(pressure detection part) which detects the internal pressure of theprocess chamber 201 and an APC (auto pressure controller) valve 244 as apressure regulator (pressure regulation part). The APC valve 244 isconfigured so that a vacuum exhaust and a vacuum exhaust stop of theinterior of the process chamber 201 can be performed by opening andclosing the APC valve 244 while operating the vacuum pump 246 and sothat the internal pressure of the process chamber 201 can be adjusted byadjusting an opening degree of the APC valve 244 based on pressureinformation detected by the pressure sensor 245 while operating thevacuum pump 246. An exhaust system mainly includes the exhaust pipe 231,the APC valve 244, and the pressure sensor 245. The vacuum pump 246 maybe regarded as being included in the exhaust system.

A seal cap 219, which serves as a furnace opening cover configured tohermetically seal a lower end opening of the manifold 209, is installedunder the manifold 209. The seal cap 219 is composed of a metal materialsuch as, e.g., stainless steel (SUS) or the like, and is formed in adisc shape. An O-ring 220 b, which is a seal making contact with thelower end portion of the manifold 209, is installed on an upper surfaceof the seal cap 219.

A rotator 267 configured to rotate a boat 217, which will be describedlater, is installed under the seal cap 219. A rotary shaft 255 of therotator 267, which is composed of a metal material such as stainlesssteel or the like and penetrates the seal cap 219, is connected to theboat 217. The rotator 267 is configured to rotate the wafers 200 byrotating the boat 217. The seal cap 219 is configured to be verticallymoved up and down by a boat elevator 115 which is an elevator mechanisminstalled outside the reaction tube 203. The boat elevator 115 isconfigured as a transfer device (transfer mechanism) which loads andunloads (transfers) the wafers 200 into and from (out of) the processchamber 201 by moving the seal cap 219 up and down.

A shutter 219 s as a furnace opening cover capable of hermetically sealthe lower end opening of the manifold 209 while moving the seal cap 219down to unload the boat 217 from the interior of the process chamber 201is installed under the manifold 209. The shutter 219 s is composed of ametal material such as stainless steel or the like, and is formed in adisc shape. An O-ring 220 c as a seal making contact with the lower endportion of the manifold 209 is installed on an upper surface of theshutter 219 s. An opening/closing operation (an up-down movementoperation or a rotational movement operation) of the shutter 219 s iscontrolled by a shutter-opening/closing mechanism 115 s.

The boat 217 serving as a substrate holder is configured to hold aplurality of wafers 200, e.g., 25 to 200 wafers, in such a state thatthe wafers 200 are arranged in a horizontal posture and in multiplestages along a vertical direction with the centers of the wafers 200aligned with one another. That is, the boat 217 is configured to arrangethe wafers 200 in a spaced-apart relationship. The boat 217 is composedof a heat resistant material such as quartz or SiC. Heat-insulatingplates 218 composed of a heat resistant material such as quartz or SiCare installed below the boat 217 in multiple stages.

A temperature sensor 263 serving as a temperature detector is installedin the reaction tube 203. Based on temperature information detected bythe temperature sensor 263, a degree of supplying electric power to theheater 207 is adjusted such that the interior of the process chamber 201has a desired temperature distribution. The temperature sensor 263 isinstalled along the inner wall of the reaction tube 203.

As illustrated in FIG. 3, the controller 121, which is a control part(control means), may be configured as a computer including a CPU(central processing unit) 121 a, a RAM (random access memory) 121 b, amemory 121 c, and an I/O port 121 d. The RAM 121 b, the memory 121 c,and the I/O port 121 d are configured to exchange data with the CPU 121a via an internal bus 121 e. An input/output device 122 formed of, e.g.,a touch panel or the like, is connected to the controller 121.

The memory 121 c is configured by, for example, a flash memory, a HDD(hard disk drive), or the like. A control program for controllingoperations of a substrate processing apparatus, a process recipe forspecifying sequences and conditions of substrate processing as describedhereinbelow, or the like is readably stored in the memory 121 c. Theprocess recipe functions as a program for causing the controller 121 toexecute each sequence in the substrate processing, as describedhereinbelow, to obtain a predetermined result. Hereinafter, the processrecipe and the control program will be generally and simply referred toas a “program.” Furthermore, the process recipe will be simply referredto as a “recipe.” When the term “program” is used herein, it mayindicate a case of including the recipe, a case of including the controlprogram, or a case of including both the recipe and the control program.The RAM 121 b is configured as a memory area (work area) in which aprogram, data, and the like read by the CPU 121 a is temporarily stored.

The I/O port 121 d is connected to the MFCs 241 a to 241 h, the valves243 a to 243 h, the pressure sensor 245, the APC valve 244, the vacuumpump 246, the temperature sensor 263, the heater 207, the rotator 267,the boat elevator 115, the shutter-opening/closing mechanism 115 s, andthe like, as described above.

The CPU 121 a is configured to read the control program from the memory121 c and execute the same. The CPU 121 a is also configured to read therecipe from the memory 121 c according to an input of an operationcommand from the input/output device 122. In addition, the CPU 121 a isconfigured to control, according to the contents of the recipe thusread, the flow-rate-adjusting operation of various kinds of gases by theMFCs 241 a to 241 h, the opening/closing operation of the valves 243 ato 243 h, the opening/closing operation of the APC valve 244, thepressure-regulating operation performed by the APC valve 244 based onthe pressure sensor 245, the driving and stopping of the vacuum pump246, the temperature-adjusting operation performed by the heater 207based on the temperature sensor 263, the operations of rotating the boat217 and adjusting the rotation speed of the boat 217 with the rotator267, the operation of moving the boat 217 up and down with the boatelevator 115, the operation of opening and closing the shutter 219 swith the shutter-opening/closing mechanism 115 s, and the like.

The controller 121 may be configured by installing, on the computer, theaforementioned program stored in an external memory 123. The externalmemory 123 may include, for example, a magnetic disc such as a HDD, anoptical disc such as a CD, a magneto-optical disc such as a MO, asemiconductor memory such as a USB memory, and the like. The memory 121c or the external memory 123 is configured as a computer-readablerecording medium. Hereinafter, the memory 121 c and the external memory123 will be generally and simply referred to as a “recording medium.”When the term “recording medium” is used herein, it may indicate a caseof including the memory 121 c, a case of including the external memory123, or a case of including both the memory 121 c and the externalmemory 123. Furthermore, the program may be supplied to the computer byusing a communication means such as the Internet or a dedicated line,instead of using the external memory 123.

(2) Substrate-Processing Process

A process sequence example of selective growth (selective filmformation) in which a film is formed by selectively growing it on asurface of a specific base among a plurality of kinds of bases exposedon a surface a wafer 200 as a substrate using the aforementionedsubstrate processing apparatus, which is one of the processes formanufacturing a semiconductor device, will be described mainly withreference to FIGS. 4, and 5A to 5G. In the following descriptions, theoperations of the respective parts constituting the substrate processingapparatus are controlled by the controller 121.

In the process sequence illustrated in FIG. 4, there are performed: stepA of forming a SiO film as a protective film 200 e on a surface of abase 200 c by supplying an O₂ gas as a processing gas to a wafer 200 inwhich an O-free first base (base 200 a) including a silicon nitride film(SiN film), an O-containing second base (base 200 b) including a siliconoxide film (SiO film), and an O- and N-free third base (base 200 c)including a single crystalline silicon (Si) are exposed on its surface;step B of adsorbing Si contained in a SiH₃R gas on respective surfacesof the base 200 b and the protective film 200 e by supplying the SiH₃Rgas as an aminosilane-based gas to the wafer 200 after the protectivefilm 200 e is formed on the surface of the base 200 c; step C ofmodifying the surfaces of the base 200 b and the protective film 200 eby supplying an F₂ gas as a fluorine-containing gas to the wafer 200after Si is adsorbed on the respective surfaces of the base 200 b andthe protective film 200 e to react Si adsorbed on the respectivesurfaces of the base 200 b and the protective film 200 e with the F₂gas; and step D of selectively forming a SiN film which is a filmcontaining Si and N as a film on the surface of the base 200 a bysupplying a SiCl₄ gas and an NH₃ gas as film-forming gases to the wafer200 after the respective surfaces of the base 200 b and the protectivefilm 200 e are modified.

Furthermore, in FIG. 4, an example in which at step D, a cycle whichnon-simultaneously performs step D1 of supplying the SiCl₄ gas to thewafer 200 and step D2 of supplying the NH₃ gas to the wafer 200 isimplemented a predetermined number of times (n times, where n is aninteger of 1 or more) is illustrated.

In the present disclosure, for the sake of convenience, the processsequence described above may sometimes be denoted as follows. The samedenotation will be used in other embodiments as described hereinbelow.

O₂→SiH₃R→F₂→(SiCl₄→NH₃)×n⇒SiN

When the term “wafer” is used herein, it may refer to a wafer itself ora laminated body of a wafer and a predetermined layer or film formed onthe surface of the wafer. In addition, when the phrase “a surface of awafer” is used herein, it may refer to a surface of a wafer itself or asurface of a predetermined layer or the like formed on a wafer.Furthermore, in the present disclosure, the expression “a predeterminedlayer is formed on a wafer” may mean that a predetermined layer isdirectly formed on a surface of a wafer itself or that a predeterminedlayer is formed on a layer or the like formed on a wafer. In addition,when the term “substrate” is used herein, it may be synonymous with theterm “wafer.”

(Wafer Charging and Boat Loading)

If a plurality of wafers 200 is charged on the boat 217 (wafercharging), the shutter 219 s is moved by the shutter-opening/closingmechanism 115 s to open the lower end opening of the manifold 209(shutter opening). Thereafter, as illustrated in FIG. 1, the boat 217supporting the plurality of wafers 200 is lifted up by the boat elevator115 and is loaded into the process chamber 201 (boat loading). In thisstate, the seal cap 219 seals the lower end of the manifold 209 via theO-ring 220 b.

As illustrated in FIG. 5A, a plurality of kinds of bases, for example, abase 200 a including a SiN film as a nitride film which is an O-freefilm, i.e., a non-oxide film, a base 200 b including a SiO film as anO-containing film, i.e., an oxide film, and a base 200 c including asingle crystalline Si as an O- and N-free substance are exposed inadvance on a surface of a wafer 200. That is, an example in which thebase 200 a is composed of a SiN film which is an insulating substance(insulator), the base 200 b is composed of a SiO film which is aninsulating substance (insulator), and the base 200 c is composed of asingle crystalline Si which is a semiconductor substance is illustratedin the present disclosure. Furthermore, as illustrated in FIG. 5A, whennatural oxide films 200 d are formed on the surface of the wafer 200,for example, a cleaning process (DHF cleaning) using a dilutedhydrofluoric acid (DHF) aqueous solution, i.e., a hydrogen fluoride (HF)aqueous solution, is performed on the wafer 200 in advance, i.e., beforeboat loading, to remove the natural oxide films 200 d formed on thesurface of the wafer 200 (natural oxide film removal). Specifically, byperforming DHF cleaning on the wafer 200 to remove the natural oxidefilms 200 d formed on the surface of the base 200 a as illustrated inFIG. 5B, the material of the base 200 a, i.e., the SiN film, is exposedon the uppermost surface of the base 200 a. Thus, uniform processing canbe performed on the surface of the base 200 a at step D as describedhereinbelow. When removing the natural oxide films 200 d formed on thesurface of the base 200 a, the natural oxide films 200 d formed on thesurface of the base 200 c exposed on the surface of the wafer 200 arealso removed, and the material of the base 200 c, i.e., the singlecrystalline Si, is also exposed on the outermost surface of the base 200c. Thus, uniform processing can be performed on the surface of the base200 c at step A as described hereinbelow.

(Pressure Regulation and Temperature Adjustment)

The interior of the process chamber 201, namely the space in which thewafers 200 are located, is vacuum-exhausted (depressurization-exhausted)by the vacuum pump 246 so as to reach a desired pressure (degree ofvacuum). In this operation, the internal pressure of the process chamber201 is measured by the pressure sensor 245. The APC valve 244 isfeedback-controlled based on the measured pressure information.Furthermore, the wafers 200 in the process chamber 201 are heated by theheater 207 to a desired processing temperature. In this operation, thedegree of supplying electric power to the heater 207 isfeedback-controlled based on the temperature information detected by thetemperature sensor 263 such that the interior of the process chamber 201has a desired temperature distribution. In addition, the rotation of thewafers 200 by the rotator 267 begins. The exhaust of the interior of theprocess chamber 201 and the heating and rotation of the wafers 200 maybe continuously performed at least until the process to the wafers 200is completed.

(Selective Growth)

Next, the following steps A to D are sequentially performed.

[Step A]

At this step, an O₂ gas is supplied to the wafer 200 in the processchamber 201, namely the wafer 200 in which the base 200 a, the base 200b, and the base 200 c are exposed on its surface, as illustrated in FIG.5B.

Specifically, the valve 243 h is opened to allow an O₂ gas to flowthrough the gas supply pipe 232 h. The flow rate of the O₂ gas isadjusted by the MFC 241 h. The O₂ gas is supplied into the processchamber 201 via the gas supply pipe 232 a and the nozzle 249 a and isexhausted from the exhaust port 231 a. At this time, the O₂ gas issupplied to the wafer 200 (O₂ gas supply). Simultaneously, the valves243 e and 243 f are opened to supply an N₂ gas into the process chamber201 via the nozzles 249 b and 249 c, respectively. The supply of the N₂gas may not be performed.

The examples of the processing conditions at this step may be describedas follows:

O₂ gas supply flow rate: 10 to 10,000 sccm or 100 to 10,000 sccm in someembodiments

O₂ gas supply time: 1 to 180 seconds or 1 to 60 seconds in someembodiments

N₂ gas supply flow rate (per gas supply pipe): 0 to 10,000 sccm or 100to 10,000 sccm in some embodiments

Processing temperature: room temperature to 600 degrees C. or 50 to 550degrees C. in some embodiments

Processing pressure: 1 to atmospheric pressure (101,325 Pa), 10 to 5,000Pa in some embodiments, or 100 to 1,000 Pa in some embodiments.

The conditions described herein are conditions under which the base 200c is oxidized without oxidizing the surface of the base 200 a.

Furthermore, in the present disclosure, the expression of the numericalrange such as “1 to 101,325 Pa” may mean that a lower limit value and anupper limit value are included in that range. Therefore, for example, “1to 101,325 Pa” may mean “1 Pa or higher and 101,325 Pa or lower.” Thesame applies to other numerical ranges.

By supplying the O₂ gas to the wafer 200 under the aforementionedconditions, as illustrated in FIG. 5C, the surface of the base 200 c canbe selectively (preferentially) oxidized while suppressing the oxidationof the surface of the base 200 a. By oxidizing the surface of the base200 c, a SiO film is formed as the protective film 200 e on the surfaceof the base 200 c. At this time, since the base 200 b is composed of aSiO film, the surface of the base 200 b is not oxidized and theprotective film 200 e is not newly formed on the surface. Such selective(preferential) oxidation is possible because the processing conditionsat this step are set to conditions under which the surface of the base200 a is not oxidized, i.e., conditions under which an oxide film (SiOfilm or SiON film) is not formed on the surface of the base 200 a. Atthis step, by performing dry oxidation under the conditions under whichthe surface of the base 200 a is not oxidized, the surface of the base200 c can be selectively oxidized, i.e., the SiO film as the protectivefilm 200 e can be selectively formed on the surface of the base 200 c.Furthermore, at this step, the film thickness controllability and filmthickness uniformity of the protective film 200 e formed on the surfaceof the base 200 c can be enhanced by oxidizing the surface of the base200 c under a pressure condition less than an atmospheric pressure (in avacuum atmosphere or a decompressed atmosphere).

The protective film 200 e formed on the surface of the base 200 cfunctions as a film for protecting the base 200 c when a F₂ gas issupplied at step C as described hereinbelow. When the F₂ gas is broughtinto contact with the surface of the base 200 c at step C as describedhereinbelow, the surface of the base 200 c may be etched and damaged byetching. By forming the protective film 200 e on the surface of the base200 c, it is possible to prevent the F₂ gas from being brought intocontact with the surface of the base 200 c at step C. Therefore, it ispossible to suppress the etching of the surface of the base 200 c and tosuppress the etching damage to the surface of the base 200 c. Inaddition, the protective film 200 e does not adversely affect eachprocessing at steps B and C.

The film thickness of the protective film 200 e formed at this step isabout 10 Å, which is smaller than the film thickness of the naturaloxide films 200 d formed on the surface of the base 200 c before the DHFcleaning. Even if the film thickness of the protective film 200 e issmall as described above, since the film thickness uniformity of theprotective film 200 e is much higher than the film thickness uniformityof the natural oxide films, it becomes possible to sufficiently suppressthe contact of the F₂ gas with the surface of the base 200 c whensupplying the F₂ gas at step C as described hereinbelow.

After the protective film 200 e is formed on the surface of the base 200c, the valve 243 h is closed to stop the supply of the O₂ gas into theprocess chamber 201. Then, the interior of the process chamber 201 isvacuum-exhausted and the gas or the like remaining within the processchamber 201 is removed from the interior of the process chamber 201. Atthis time, the valves 243 d to 243 f are opened to supply a N₂ gas intothe process chamber 201 via the nozzles 249 a to 249 c. The N₂ gassupplied from the nozzles 249 a to 249 c acts as a purge gas. Thus, theinterior of the process chamber 201 is purged (purge).

As the O-containing gas, it may be possible to use, in addition to theO₂ gas, an O-containing gas such as a nitrous oxide (N₂O) gas, a nitricoxide (NO) gas, a nitrogen dioxide (NO₂) gas, an ozone (O₃) gas, watervapor (H₂O gas), a carbon monoxide (CO) gas, a carbon dioxide (CO₂) gas,or the like.

As the inert gas, it may be possible to use, in addition to the N₂ gas,a rare gas such as an Ar gas, a He gas, a Ne gas, a Xe gas, or the like.This also applies to each step as described hereinbelow.

[Step B]

After step A is completed, a SiH₃R gas is supplied to the wafer 200 inthe process chamber 201, namely the wafer 200 after the protective film200 e is formed on the surface of the base 200 c.

Specifically, the valve 243 g is opened to allow a SiH₃R gas to flowinto the gas supply pipe 232 g. The flow rate of the SiH₃R gas isadjusted by the MFC 241 g. The SiH₃R gas is supplied into the processchamber 201 via the gas supply pipe 232 c and the nozzle 249 c and isexhausted from the exhaust port 231 a. At this time, the SiH₃R gas issupplied to the wafer 200 (SiH₃R gas supply). Simultaneously, the valves243 d and 243 e are opened to supply an N₂ gas into the process chamber201 via the nozzles 249 a and 249 b, respectively. The supply of the N₂gas may not be performed.

The examples of the processing conditions at this step may be describedas follows:

SiH₃R gas supply flow rate: 1 to 2,000 sccm or 1 to 500 sccm in someembodiments

SiH₃R gas supply time: 1 second to 60 minutes

N₂ gas supply flow rate (per gas supply pipe): 0 to 10,000 sccm

Processing temperature: room temperature (25 degrees C.) to 600 degreesC. or room temperature to 450 degrees C. in some embodiments

Processing pressure: 1 to 2,000 Pa or 1 to 1,000 Pa in some embodiments.

The conditions described herein are conditions under which the SiH₃R gasis not gas-phase decomposed (pyrolyzed) in the process chamber 201.Furthermore, the base 200 b and the protective film 200 e includessurfaces terminated with hydroxyl groups (OH) over the entire region(entire surface). The base 200 a includes a surface in which manyregions are not OH-terminated, namely a surface in which some regionsare OH-terminated.

By supplying the SiH₃R gas to the wafer 200 under the aforementionedconditions, as illustrated in FIG. 5D, Si contained in the SiH₃R gas canbe selectively (preferentially) adsorbed on the surface of the base 200b while suppressing the adsorption of Si contained in the SiH₃R gas onthe surface of the base 200 a. At this time, Si contained in the SiH₃Rgas can be selectively (preferentially) adsorbed on the surface of theprotective film 200 e. Furthermore, at this time, Si contained in theSiH₃R gas may be adsorbed on a portion of the surface of the base 200 a,but the adsorption amount of Si is smaller than the adsorption amount ofSi on the respective surfaces of the base 200 b and the protective film200 e. The reason why such selective (preferential) adsorption ispossible is because the processing conditions at this step are set tothe conditions under which the SiH₃R gas is not gas-phase decomposed inthe process chamber 201. Another reason is because the respectivesurfaces of the base 200 b and the protective film 200 e areOH-terminated over the entire region, whereas many regions of thesurface of the base 200 a are not OH-terminated (some regions of thesurface are OH-terminated). At this step, since the SiH₃R gas is notgas-phase decomposed in the process chamber 201, Si contained in SiH₃Ris not multiple-deposited on the respective surfaces of the bases 200 aand 200 b and the protective film 200 e. At this step, on the respectivesurfaces of the base 200 b and the protective film 200 e, theOH-termination formed on the entire region of the surfaces reacts withSiH₃R to chemisorb Si contained in SiH₃R on the entire region of therespective surfaces of the base 200 b and the protective film 200 e. Onthe other hand, since the OH-termination does not exist in many regionsof the surface of the base 200 a, Si contained in SiH₃R is notchemisorbed in such many regions. However, the OH-termination formed insome regions of the surface of the base 200 a and SiH₃R may react witheach other to chemisorb Si contained in SiH₃R on such some regions. Inaddition, when Si contained in SiH₃R is chemisorbed on the surface ofthe base, it is chemisorbed in a state where H is bonded to Si.

Furthermore, if the supply of the SiH₃R gas is continued for apredetermined period of time, the chemisorption of Si on the respectivesurfaces of the base 200 b and the protective film 200 e is saturated.That is, the chemisorption of Si on the respective surfaces of the base200 b and the protective film 200 e is self-limited. In other words,when a Si layer of one layer is formed on the respective surfaces of thebase 200 b and the protective film 200 e, Si is no longer chemisorbed onthe respective surfaces of the base 200 b and the protective film 200 e.As a result, the amounts of Si adsorbed on the respective surfaces ofthe base 200 b and the protective film 200 e become substantiallyuniform over the entire region of the respective surfaces of the base200 b and the protective film 200 e.

After Si is selectively adsorbed on the respective surfaces of the base200 b and the protective film 200 e, the valve 243 g is closed to stopthe supply of the SiH₃R gas into the process chamber 201. Then, the gasor the like, which remains within the process chamber 201, is removedfrom the interior of the process chamber 201 according to the sameprocessing procedures as those of the purge at step A.

As the aminosilane-based gas, it may be possible to use, in addition tothe aforementioned monoaminosilane gas containing one amino group in onemolecule, a diaminosilane (SiH₂RR′) gas containing two amino groups inone molecule, or a triaminosilane (SiHRR′R″) gas containing three aminogroups in one molecule.

In addition, as the aminosilane-based gas, it may be possible to use anaminosilane compound represented by the following chemical formula [1]:

SiA_(x)[(NB₂)_((4-x))]  [1]

In the formula [1], A indicates a hydrogen atom, an alkyl group such asa methyl group, an ethyl group, a propyl group or a butyl group, or analkoxy group such as a methoxy group, an ethoxy group, a propoxy groupor a butoxy group. The alkyl group may be not only a linear alkyl groupbut also a branched alkyl group such as an isopropyl group, an isobutylgroup, a secondary butyl group, a tertiary butyl group or the like. Thealkoxy group may be not only a linear alkoxy group but also a branchedalkoxy group such as an isopropoxy group, an isobutoxy group or thelike. B indicates a hydrogen atom or an alkyl group such as a methylgroup, an ethyl group, a propyl group, a butyl group or the like. Thealkyl group may be not only a linear alkyl group but also a branchedalkyl group such as an isopropyl group, an isobutyl group, a secondarybutyl group, a tertiary butyl group or the like. A plurality of A's maybe equal or different, two B's may be equal or different, and x is aninteger of 1 to 3.

[Step C]

After step B is completed, a F₂ gas is supplied to the wafer 200 in theprocess chamber 201, namely the wafer 200 after Si is selectivelyadsorbed on the respective surfaces of the base 200 b and the protectivefilm 200 e.

Specifically, the valve 243 b is opened to allow a F₂ gas to flow intothe gas supply pipe 232 b. The flow rate of the F₂ gas is adjusted bythe MFC 241 b. The F₂ gas is supplied into the process chamber 201 viathe nozzle 249 b and is exhausted from the exhaust port 231 a. At thistime, the F₂ gas is supplied to the wafer 200 (F₂ gas supply).Simultaneously, the valves 243 d and 243 f are opened to supply a N₂ gasinto the process chamber 201 via the nozzles 249 a and 249 c. The supplyof the N₂ gas may not be performed.

The examples of the processing conditions at this step may be describedas follows:

F₂ gas supply flow rate: 1 to 2,000 sccm or 1 to 500 sccm in someembodiments

F₂ gas supply time: 1 second to 60 minutes

Processing temperature: room temperature to 550 degrees C. or roomtemperature to 450 degrees C. in some embodiments.

Other conditions may be similar to the processing conditions of step B.The conditions described herein are conditions under which therespective surfaces of the base 200 b and the protective film 200 e arenot etched, and conditions under which the respective surfaces of thebase 200 b and the protective film 200 e are modified (F-terminated), aswill be described later.

By supplying the F₂ gas to the wafer 200 under the aforementionedconditions, the respective surfaces of the base 200 b and the protectivefilm 200 e can be modified without etching by reacting Si adsorbed onthe respective surfaces of the base 200 b and the protective film 200 eand the F₂ gas with each other. At this time, since the surface of thebase 200 c is protected by the protective film 200 e, it is possible toprevent the F₂ gas from being brought into contact with the surface ofthe base 200 c. Thus, it is possible to avoid the etching damage to thesurface of the base 200 c. The modified base 200 b and protective film200 e include F-terminated (SiF-terminated) surfaces. Furthermore, whenattention is paid to atoms existing on the respective outermost surfacesof the modified base 200 b and protective film 200 e, it can be saidthat the base 200 b and the protective film 200 e include F-terminatedsurfaces, respectively. In addition, when attention is paid to the atomsexisting on the respective outermost surfaces of the modified base 200 band protective film 200 e and atoms bonded to the atoms, it can be saidthat the base 200 b and the protective film 200 e include SiF-terminatedsurfaces, respectively. In the present disclosure, for the sake ofconvenience, it is assumed that the former name will be mainly used.Since the respective surfaces of the base 200 b and the protective film200 e are F-terminated, film formation reaction is not performed on therespective surfaces of the base 200 b and the protective film 200 e atstep D as described hereinbelow. To be precise, it is possible toprolong the time until the film formation reaction occurs, namely theincubation time. Furthermore, in the case in which the organiccomponents contained in SiH₃R remain on the respective surfaces of thebase 200 b and the protective film 200 e, when Si adsorbed on therespective surfaces of the base 200 b and the protective film 200 ereacts with the F₂ gas, the organic components are removed from therespective surfaces of the base 200 b and the protective film 200 e.

As illustrated in FIG. 5E, at this step, the respective surfaces of thebase 200 b and the protective film 200 e can be selectively(preferentially) modified while suppressing the modification of thesurface of the base 200 a. At this time, a portion of the surface of thebase 200 a may be modified, but the amount of the modification issmaller than the amount of the modification of the respective surfacesof the base 200 b and the protective film 200 e. Such selective(preferential) modification is possible because Si is not adsorbed onmany regions of the surface of the base 200 a after step B is performed,whereas Si is adsorbed on the entire region of the respective surfacesof the base 200 b and the protective film 200 e. Since Si is notadsorbed in many regions of the surface of the base 200 a, the reactionbetween Si and F₂ is not performed, and as a result, the F-terminationis not formed in such many regions. However, as described above, Si maybe adsorbed on the partial region of the surface of the base 200 a, andin that case, the F-termination may be formed on such partial region. Onthe other hand, on the entire region of the respective surfaces of thebase 200 b and the protective film 200 e, Si adsorbed on the surfacesreacts with F₂ to generate an F-containing radical, and a very stableF-termination (SiF-termination) is formed on the entire region of thesurfaces thereof by the action of such radical. The F-containing radicalmay include F, SiF, SiF₂, SiF₃, SiHF, SiH₂F, SiHF₂, and the like.

Furthermore, as described above, the amounts of Si adsorbed on the base200 b and the protective film 200 e at step B are set to besubstantially uniform over the entire region of the respective surfacesof the base 200 b and the protective film 200 e. Therefore, at thisstep, the amounts of the F-containing radical generated on therespective surfaces of the base 200 b and the protective film 200 ebecome substantially uniform over the entire in-plane region thereof. Asa result, the modification of the base 200 b and the protective film 200e described above is performed substantially uniformly over the entireregion of the surfaces thereof.

Furthermore, since Si is not adsorbed in many regions of the surface ofthe base 200 a as described above, the reaction between Si and F₂ is notperformed, no F-containing radical is generated, and such many regionsare not modified. However, when Si is adsorbed in the partial region ofthe surface of the base 200 a, Si and F₂ react with each other in thepartial region thereof to generate the F-containing radical, and thepartial region thereof may be modified, as described above. As a result,the surface of the base 200 a is hardly damaged by etching, andadsorption sites are kept in many regions of the surface.

After the respective surfaces of the base 200 b and the protective film200 e among the bases 200 a and 200 b and the protective film 200 e areselectively modified, the valve 243 b is closed to stop the supply ofthe F₂ gas into the process chamber 201. Then, the gas or the like,which remains within the process chamber 201, is removed from theinterior of the process chamber 201 according to the same processingprocedures as those of the purge at step A.

As the fluorine-containing gas, it may be possible to use, in additionto the F₂ gas, a chlorine trifluoride (ClF₃) gas, a chlorine fluoridegas (ClF) gas, an F₂+nitric oxide (NO) gas, a ClF+NO gas, a nitrogentrifluoride (NF₃) gas, a tungsten hexafluoride (WF₆) gas, a nitrosylfluoride (FNO) gas, or a mixed gas thereof.

[Step D]

After step C is completed, a SiCl₄ gas and an NH₃ gas are supplied tothe wafer 200 in the process chamber 201, namely the wafer 200 after therespective surfaces of the base 200 b and the protective film 200 e aremodified. At this step, steps D1 and D2 are sequentially performed.

[Step D1]

At this step, a SiCl₄ is applied to the wafer 200 in the process chamber201, namely the wafer 200 after the respective surfaces of the base 200b and the protective film 200 e among the bases 200 a and 200 b and theprotective film 200 e are selectively modified.

Specifically, the valve 243 a is opened to allow a SiCl₄ gas to flowinto the gas supply pipe 232 a. The flow rate of the SiCl₄ gas isadjusted by the MFC 241 a. The SiCl₄ gas is supplied into the processchamber 201 via the nozzle 249 a and is exhausted from the exhaust port231 a. At this time, the SiCl₄ gas is supplied to the wafer 200 (SiCl₄gas supply). Simultaneously, the valves 243 e and 243 f may be opened tosupply an N₂ gas into the process chamber 201 via the nozzles 249 b and249 c, respectively.

The examples of the processing conditions at this step may be describedas follows:

SiCl₄ gas supply flow rate: 1 to 2,000 sccm or 10 to 1,000 sccm in someembodiments

SiCl₄ gas supply time: 1 to 180 seconds or 10 to 120 seconds in someembodiments

Processing temperature: 350 to 600 degrees C. or 400 to 550 degrees C.in some embodiments

Processing pressure: 1 to 2,000 Pa or 10 to 1,333 Pa in someembodiments.

Other processing conditions may be similar to the processing conditionsof step B.

By supplying the SiCl₄ gas to the wafer 200 under the aforementionedconditions, a Si-containing layer containing Cl is formed on the surfaceof the base 200 a including unmodified regions of the bases 200 a and200 b and the protective film 200 e. That is, the Si-containing layercontaining Cl is formed starting from the unmodified region of the base200 a, namely the region in which the adsorption sites are kept. TheSi-containing layer containing Cl is formed by physisorption orchemisorption of SiCl₄ on the surface of the base 200 a, chemisorptionof a substance (SiCl_(x)) in which a portion of SiCl₄ is decomposed,deposition of Si by pyrolysis of SiCl₄, or the like. The Si-containinglayer containing Cl may be an adsorption layer of SiCl₄ or SiCl_(x) (aphysisorption layer or a chemisorption layer), or may be a deposit layerof Si containing Cl. In the present disclosure, the Si-containing layercontaining Cl will be simply referred to as a Si-containing layer.

At this step, the Si-containing layer can be selectively formed on thesurface of the base 200 a while suppressing the formation of theSi-containing layer on the respective surfaces of the base 200 b and theprotective film 200 e. In addition, when the respective surfaces of thebase 200 b and the protective film 200 e are insufficiently modified dueto certain factors, the Si-containing layer may be very slightly formedon the respective surfaces of the base 200 b and the protective film 200e, but also in this case, the thickness of the Si-containing layerformed on the respective surfaces of the base 200 b and the protectivefilm 200 e becomes much smaller than the thickness of the Si-containinglayer formed on the surface of the base 200 a. Such selective formationof the Si-containing layer is possible because the F-terminationexisting on the respective surfaces of the base 200 b and the protectivefilm 200 e acts as a factor that inhibits the formation of theSi-containing layer (adsorption of Si) on the respective surfaces of thebase 200 b and the protective film 200 e, i.e., as an inhibitor.Furthermore, the F-terminations existing on the respective surfaces ofthe base 200 b and the protective film 200 e are stably kept withoutbeing eliminated even when this step is performed.

After the Si-containing layer is formed on the surface of the base 200a, the valve 243 a is closed to stop the supply of the SiCl₄ gas intothe process chamber 201. Then, the gas or the like, which remains withinthe process chamber 201, is removed from the interior of the processchamber 201 according to the same processing procedures as those of thepurge at step A (purge).

As the precursor gas (film-forming gas), it may be possible to use, inaddition to the SiCl₄ gas, a chlorosilane-based gas such as amonochlorosilane (SiH₃Cl, abbreviation: MCS) gas, a dichlorosilane(SiH₂Cl₂, abbreviation: DCS) gas, a trichlorosilane (SiHCl₃,abbreviation: TCS) gas, a hexachlorodisilane (Si₂Cl₆, abbreviation:HCDS) gas, an octachlorotrisilane (Si₃Cl₈, abbreviation: OCTS) gas orthe like, a bromosilane-based gas such as a tetrabromosilane (SiBr₄) gasor the like, or an iodosilane-based gas such as a tetraiodosilane (SiI₄)gas or the like.

[Step D2]

At this step, an NH₃ gas is supplied to the wafer 200 in the processchamber 201, namely to the Si-containing layer formed on the surface ofthe base 200 a.

Specifically, the valve 243 c is opened to allow an NH₃ gas to flow intothe gas supply pipe 232 c. The flow rate of the NH₃ gas is adjusted bythe MFC 241 c. The NH₃ gas is supplied into the process chamber 201 viathe nozzle 249 c and is exhausted from the exhaust port 231 a. At thistime, the NH₃ gas is supplied to the wafer 200 (NH₃ gas supply).Simultaneously, the valves 243 d and 243 e may be opened to supply an N₂gas into the process chamber 201 via the nozzles 249 a and 249 b,respectively.

The examples of the processing conditions at this step may be describedas follows:

NH₃ gas supply flow rate: 10 to 10,000 sccm

NH₃ gas supply time: 1 to 60 seconds or 5 to 50 seconds in someembodiments

Processing pressure: 1 to 4,000 Pa or 1 to 1,333 Pa in some embodiments.

Other processing conditions may be similar to the processing conditionsof step B.

By supplying the NH₃ gas to the wafer 200 under the aforementionedconditions, at least a portion of the Si-containing layer formed on thesurface of the base 200 a is nitrided. By nitriding the Si-containinglayer, a layer containing Si and N, i.e., a silicon nitride layer (SiNlayer), is formed on the surface of the base 200 a. When forming the SiNlayer, an impurity such as Cl contained in the Si-containing layerconstitutes a gaseous substance containing at least Cl in the process ofthe nitriding reaction of the Si-containing layer with the NH₃ gas, andis discharged from the interior of the process chamber 201. Thus, theSiN layer becomes a layer containing a smaller amount of impurity suchas Cl or the like than that of the Si-containing layer formed at stepD1. Furthermore, the respective surfaces of the base 200 b and theprotective film 200 e are kept without being nitrided even when thisstep is performed. That is, the respective surfaces of the base 200 band the protective film 200 e are stably kept while being F-terminatedwithout being nitrided (NH-terminated).

After the SiN layer is formed on the surface of the base 200 a, thevalve 243 c is closed to stop the supply of the NH₃ gas into the processchamber 201. Then, the gas or the like, which remains within the processchamber 201, is removed from the interior of the process chamber 201according to the same processing procedures as those of the purge atstep A (purge).

As the reaction gas (film-forming gas), it may be possible to use, inaddition to the NH₃ gas, for example, a hydrogen nitride-based gas suchas a diazene (N₂H₂) gas, a hydrazine (N₂H₄) gas, a N₃H₈ gas, or thelike.

[Performing a Predetermined Number of Times]

A cycle which non-simultaneously, i.e., non-synchronously, performssteps D1 and D2 described above is implemented a predetermined number oftimes (n times, where n is an integer of 1 or more). Thus, a SiN filmcan be selectively formed on the surface of the base 200 a among thebases 200 a and 200 b and the protective film 200 e exposed on thesurface of the wafer 200, as illustrated in FIG. 5F. The aforementionedcycle may be repeated multiple times. That is, the thickness of the SiNlayer formed per one cycle may be set smaller than a desired filmthickness, and the aforementioned cycle may be repeated multiple timesuntil the film thickness of a film formed by laminating the SiN layerbecomes equal to the desired film thickness.

Furthermore, when performing steps D1 and D2, since the F-terminationsexisting on the respective surfaces of the base 200 b and the protectivefilm 200 e are kept without being eliminated, the action as theinhibitor is maintained and no SiN film is formed on the respectivesurfaces of the base 200 b and the protective film 200 e. However, ifthe respective surfaces of the base 200 b and the protective film 200 eare not sufficiently modified due to certain factors, the SiN film maybe very slightly formed on the respective surfaces of the base 200 b andthe protective film 200 e, but also in this case, the thickness of theSiN film formed on the respective surfaces of the base 200 b and theprotective film 200 e becomes much smaller than the thickness of the SiNfilm formed on the surface of the base 200 a. In the present disclosure,the expression “the SiN film is selectively formed on the surface of thebase 200 a” among the bases 200 a and 200 b and the protective film 200e may include not only a case where no SiN film is formed on therespective surfaces of the base 200 b and the protective film 200 e, butalso a case where a very thin SiN film is formed on the respectivesurfaces of the base 200 b and the protective film 200 e, as describedabove.

(After-Purge and Atmospheric Pressure Return)

After the selective formation of the SiN film on the base 200 a iscompleted, the N₂ gas as a purge gas is supplied from each of thenozzles 249 a to 249 c into the process chamber 201 and is exhaustedfrom the exhaust port 231 a. Thus, the interior of the process chamber201 is purged and the gas or the reaction byproduct, which remainswithin the process chamber 201, is removed from the interior of theprocess chamber 201 (after-purge). Thereafter, the internal atmosphereof the process chamber 201 is substituted by an inert gas (inert gassubstitution). The internal pressure of the process chamber 201 isreturned to an atmospheric pressure (atmospheric pressure return).

(Boat Unloading and Wafer Discharging)

The seal cap 219 is moved down by the boat elevator 115 to open thelower end of the manifold 209. Then, the processed wafers 200 supportedon the boat 217 are unloaded from the lower end of the manifold 209 tothe outside of the reaction tube 203 (boat unloading). After the boatunloading, the shutter 219 s is moved so that the lower end opening ofthe manifold 209 is sealed by the shutter 219 s via the O-ring 220 c(shutter closing). The processed wafers 200 are unloaded to the outsideof the reaction tube 203 and are subsequently discharged from the boat217 (wafer discharging).

Furthermore, as illustrated in FIG. 5G, the F-terminations existing onthe respective surfaces of the base 200 b and the protective film 200 eare dissociated by reacting with a predetermined reaction product,specifically, moisture (H₂O) in the atmosphere, when the processedwafers 200 are exposed to the atmosphere. That is, the F-terminationsexisting on the respective surfaces of the base 200 b and the protectivefilm 200 e can be removed by the exposure of the processed wafers 200 tothe atmosphere. By removing the F-terminations from the respectivesurfaces of the base 200 b and the protective film 200 e, the respectivesurface states of the base 200 b and the protective film 200 e arereset, and the film-forming process can be performed on the respectivesurfaces of the base 200 b and the protective film 200 e at a subsequentstep.

(3) Effects According to the Present Embodiments

According to the present embodiments, one or more effects as set forthbelow may be achieved.

(a) By performing steps A to D, it becomes possible to selectively formthe SiN film on the surface of the base 200 a among the bases 200 a, 200b, and 200 c exposed on the surface of the wafer 200. This makes itpossible to simplify their processes, such as omitting a patterningprocess including photolithography, for example, when manufacturing asemiconductor device. As a result, it is possible to improve theproductivity of the semiconductor device and to reduce the manufacturingcost.

(b) By forming the SiO film as the protective film 200 e on the surfaceof the base 200 c at step A, since the F₂ gas is not brought intocontact the surface of the base 200 c at step C, it is possible tosuppress the etching damage to the surface of the base 200 c. That is,it is possible to modify the respective surfaces of the base 200 b andthe protective film 200 e while suppressing the etching damage to thebase 200 c by the F₂ gas at step C.

In this case, it may also be considered that the natural oxide film (SiOfilm) formed on the surface of the base 200 c before the DHF cleaning isused as the protective film. However, since the natural oxide film has anon-uniform thickness, when the natural oxide film is used as theprotective film, the surface of the base 200 c may be etched and damagedby etching by bringing the F₂ gas into contact with the base 200 c in aportion where the film thickness of the natural oxide film is small atstep C.

(c) Since the film thickness of the protective film 200 e is as small asabout 10 Å, it may not be necessary to perform the step of removing theprotective film 200 e after the selective growth is completed. In thiscase, since the manufacturing process of the semiconductor device can besimplified, it is possible to improve the productivity of thesemiconductor device and to reduce the manufacturing cost. However, whenthe SiO film formed as the protective film 200 e influences the devicecharacteristics or the like, it is desirable to remove the protectivefilm 200 e. In that case, it is possible to remove the protective film200 e by, for example, DHF cleaning or the like.

(d) By performing the DHF cleaning to remove the natural oxide films 200d formed on the surface of the base 200 a and exposing the surface ofthe base 200 c before performing step A, it is possible to form the SiNfilm with high film thickness uniformity on the surface of the base 200c at step D. Furthermore, by removing the natural oxide films 200 dformed on the surface of the base 200 c to expose the surface of thebase 200 c, it is possible to form the protective film 200 e with highfilm thickness uniformity on the surface of the base 200 c by uniformlyoxidizing the surface of the base 200 c at step A.

(e) At step B, the amounts of Si selectively (preferentially) adsorbedon the base 200 b and the protective film 200 e can be set to besubstantially uniform over the entire region of the respective surfacesof the base 200 b and the protective film 200 e. This makes it possibleto substantially uniformly modify the entire region of the respectivesurfaces of the base 200 b and the protective film 200 e at step C. As aresult, it is possible to substantially uniformly and reliably inhibitthe formation of the SiN film on the base 200 b and the protective film200 e over the entire region of the surfaces thereof at step D. That is,it is possible to enhance the selectivity in the selective growth.

(f) By exposing the processed wafer 200 to the atmosphere afterperforming step D, it is possible to eliminate the F-terminations asinhibitors existing on the respective surfaces of the base 200 b and theprotective film 200 e. As described above, since the F-terminations canbe easily removed, it is may not be necessary to separately prepare astep of removing the inhibitors. Thus, it is possible to simplify themanufacturing process of the semiconductor device, to improve theproductivity of the semiconductor device, and to reduce themanufacturing cost.

(g) Since at least one selected from the group of steps A to D or eachof steps A to D in some embodiments is performed in a non-plasmaatmosphere, it is possible to avoid plasma damage to the wafer 200, andalso to apply it to the process concerned with plasma damage of thepresent disclosure.

(h) The effects mentioned above can be similarly achieved in the casewhere an oxygen-containing gas other than the O₂ gas is used, or in thecase where an aminosilane-based gas other than the SiHR₃ gas is used, orin the case where a fluorine-containing gas other than the F₂ gas isused, or in the case where a precursor gas other than the SiCl₄ gas isused, or in the case where a reaction gas other than the NH₃ gas isused, or in the case where an inert gas other than the N₂ gas is used.

Other Embodiments of the Present Disclosure

While one or more embodiments of the present disclosure have beenspecifically described above, the present disclosure is not limited tothe aforementioned embodiments but may be variously modified withoutdeparting from the spirit of the present disclosure.

In the aforementioned embodiments, there has been described an examplein which Si is selectively adsorbed on the respective surfaces of thebase 200 b and the protective film 200 e by supplying theaminosilane-based gas to the wafer 200 at step B, and the respectivesurfaces of the base 200 b and the protective film 200 e are modifiedwithout etching by supplying the F-containing gas to the wafer 200 toreact Si adsorbed on the respective surfaces of the base 200 b and theprotective film 200 e with the F-containing gas at step C, but thepresent disclosure is not limited to the aforementioned embodiments. Forexample, at step C, the F-containing radical is generated by supplyingthe F-containing gas in an atmosphere in which a pseudo catalyst existsand the respective surfaces of the base 200 b and the protective film200 e may be modified without etching using the F-containing radicalthus generated. That is, at step C, the F-containing radical isgenerated by supplying the F-containing gas into the process chamber 201accommodating the pseudo catalyst, and the respective surfaces of thebase 200 b and the protective film 200 e among the bases 200 a and 200 band the protective film 200 e may be selectively (preferentially)modified without etching by supplying the radical thus generated to thesurface of the wafer 200. In this case, step B cannot be performed.

The term “pseudo catalyst” herein refers to a substance of promoting thedecomposition of the F-containing gas and urging the generation of theF-containing radical from the F-containing gas. The generation of theF-containing radical from the F-containing gas can be promoted by thepseudo catalytic action occurring by bringing the F-containing gas intocontact with the pseudo catalyst to efficiently generate theF-containing radical.

As the pseudo catalyst, it may be possible to use, for example, Si of asolid whose outermost surface is not covered with a natural oxide film(SiO film), i.e., a Si member is exposed by exposing a Si material onthe outermost surface. For example, a wafer made of Si from which thenatural oxide film formed on the outermost surface is removed by DHFcleaning or the like, for example, a bare Si wafer (hereinafter,referred to as a bare wafer), may be used as such a member. In addition,the natural oxide film is formed on the outermost surface of the barewafer stored in the atmosphere and the Si material is not exposed on theoutermost surface, and therefore, the bare wafer cannot be used as thepseudo catalyst as it is. In order for the bare wafer to act as thepseudo catalyst, it may be necessary to remove the natural oxide filmformed on the outermost surface of the bare wafer when performing step Cand to create a state in which the Si material is exposed on theoutermost surface.

When the bare wafer is used as the pseudo catalyst, the bare wafer fromwhich the Si material is exposed on the uppermost surface is held at apredetermined position of the boat 217 together with the wafer 200 to beprocessed, and the bare wafer as the pseudo catalyst can be accommodatedin the process chamber 201 by loading the boat 217 into the processchamber 201 in that state. Furthermore, in this case, it is desirablethat the bare wafer as the pseudo catalyst and the wafer 200 to beprocessed be alternately charged on the boat 217 every other sheet, andthe bare wafer be arranged directly above the base 200 b and just abovethe protective film 200 e by allowing the upper surface of the wafer 200to be processed and the surface of the bare wafer as the pseudo catalystto face each other. In this case, at step C, the F-containing radicalcan be efficiently generated by bringing the F-containing gas intocontact with the bare wafer as the pseudo catalyst, and the F-containingradical efficiently generated in this way can be efficiently supplied toeach of the base 200 b and the protective film 200 e. As a result, itbecomes possible to appropriately modify the respective surfaces of thebase 200 b and the protective film 200 e.

The processing procedures and processing conditions for the selectivegrowth in this case may be similar to the processing procedures andprocessing conditions of the aforementioned embodiments, except that thebare wafer as the pseudo catalyst is set in the boat 217 and step B isnot performed, as in the gas supply sequence illustrated below.

O₂→Si+F₂→(SiCl₄→NH₃)×n⇒SiN

Even in this case, the same effects as those of the aforementionedembodiments may be achieved. Furthermore, by supplying the F-containinggas in an atmosphere in which the pseudo catalyst exists at step C, itis possible to increase the amount of the F-containing radical generatedby more promoting the generation of the F-containing radical in theprocess chamber 201 than in the case where the F-containing gas issupplied in an atmosphere in which the pseudo catalyst does not exist.As a result, by promoting the modification of the respective surfaces ofthe base 200 b and the protective film 200 e at step C, it is possibleto appropriately perform the selective formation of the SiN film on thesurface of the base 200 a. Moreover, by using the pseudo catalyst, it ispossible to lower the processing temperature at step C, and toeffectively suppress the etching of the surface of the base 200 a or theetching damage to the surface of the base 200 a at step C.

In addition, instead of the bare wafer, a plate made of Si (Si plate), achip made of Si (Si chip), a piece made of Si (Si piece), a block madeof Si (Si block), or the like may be used as the pseudo catalyst. Evenwhen these are used as the pseudo catalyst, it may be necessary toremove the natural oxide film formed on their outermost surfaces and tocreate a state in which the Si material is exposed on the outermostsurfaces, as in the case of using the bare wafer as the pseudo catalyst.

Furthermore, before performing step C, a Si film is formed (precoated)in advance on the surface of any member (the inner wall of the reactiontube 203, the surface of the boat 217, or the like) in the processchamber 201, and this Si film (precoated film) may also be used as thepseudo catalyst. The Si film as the precoated film may be formed, forexample, by using a silane-based gas such as a monosilane (SiH₄) gas orthe like and by a CVD method. The Si film may be a Si film in anamorphous (non-crystalline) state, a Si film in a poly (polycrystalline)state, or a Si film in a mixed state of amorphous and polycrystal.

The examples of the processing conditions when forming the Si film maybe described as follows:

SiH₄ gas supply flow rate: 10 to 2,000 sccm

N₂ gas supply flow rate (per gas supply pipe): 0 to 10,000 sccm

Gas supply time: 10 to 400 minutes

Processing temperature: 450 to 550 degrees C. or 450 to 530 degrees C.in some embodiments

Processing pressure: 1 to 900 Pa.

In this case, at step C, the F-containing radical can be efficientlygenerated by bringing the F-containing gas into contact with the Si film(precoated film) as the pseudo catalyst, and the F-containing radicalefficiently generated in this way can be efficiently supplied to thebase 200 b and the protective film 200 e. As a result, it becomespossible to appropriately modify the respective surfaces of the base 200b and the protective film 200 e.

Furthermore, in addition to the Si film, a SiN film, a silicon carbidefilm (SiC film), a silicon carbonitride film (SiCN film), a silicon-richSiN film (SiRN film), a silicon-rich SiC film (SiRC film), asilicon-rich SiCN film (SiRCN film), or the like may be used as theprecoated film. That is, in addition to Si, a Si-containing filmcontaining C or N may be used as the precoated film. The SiN film, theSiC film, the SiCN film, the SiRN film, the SiRC film, and the SiRCNfilm as the precoated films may be formed, for example, using anaminosilane-based gas such as an ethylmethylaminosilane(SiH₃[N(CH₃)(C₂H₅)]) gas, a dimethylaminosilane (SiH₃[N(CH₃)₂]) gas, adiisopropylaminosilane (SiH₃[N(C₃H₇)₂]) gas, a disecondarybutylaminosilane (SiH₃[H(C₄H₉)₂]) gas or the like and by the CVD method.The processing conditions at this time may be similar to the processingconditions when forming the Si film as the precoated film describedabove. Furthermore, the aminosilane-based gas is a gas containing Si andan amino group, and may be a gas containing at least Si, N, and C asconstituent elements.

Also, in these cases, at step C, the F-containing radical can beefficiently generated by bringing the F-containing radicals into contactwith the SiN film, the SiC film, the SiCN film, the SiRN film, the SiRCfilm, or the SiRCN film (precoated film) as the pseudo catalyst, and theF-containing radical efficiently generated in this way can beefficiently supplied to each of the base 200 b and the protective film200 e. As a result, it becomes possible to appropriately modify therespective surfaces of the base 200 b and the protective film 200 e.

The processing procedures and processing conditions in the selectivegrowth when these precoated films are used as the pseudo catalysts maybe similar to the processing procedures and processing conditions of theaforementioned embodiments except that these films are precoated on thesurface of any member in the process chamber 201 and step B is notperformed. As described above, even when the precoated film is used asthe pseudo catalyst, the same effects as those when the bare wafer isused as the pseudo catalyst may be achieved. The precoated film in thiscase may be referred to as a pseudo catalyst film or a pseudo catalystprecoated film.

In addition, after the wafer 200 to be processed is accommodated in theprocess chamber 201 and before step C is performed, a Si film is formedon the surface of the wafer 200, i.e., on the respective surfaces of thebase 200 a and 200 b and the protective film 200 e, and this Si film mayalso be used as the pseudo catalyst, i.e., the pseudo catalyst film. Asthe pseudo catalyst film, in addition to the Si film, a SiN film, a SiCfilm, a SiCN film, a SiRN film, a SiRC film, a SiRCN film, or the likemay be used. That is, in addition to Si, a Si-containing film containingC or N may be used as the pseudo catalyst film. A gas and processingconditions used when forming the Si film, the SiN film, the SiC film,the SiCN film, the SiRN film, the SiRC film, or the SiRCN film as thepseudo catalyst film may be similar to the gas and the processingconditions used when forming the precoated film described above.

In these cases, at step C, the F-containing radical can be efficientlygenerated by bringing the F-containing gas into contact with the pseudocatalyst film, and the F-containing radical efficiently generated inthis way can be supplied to each of the base 200 b and the protectivefilm 200 e. That is, the respective surfaces of the base 200 b and theprotective film 200 e can be modified so as to be F-terminated. Inaddition, at this time, the pseudo catalyst film formed on the surfaceof the base 200 a is etched and the adsorption site is exposed on thesurface of the base 200 a. At this time, the surface of the base 200 amay be slightly etched, but also in that case, the etching amount issmall and the adsorption site on its surface is kept. The base 200 b andthe protective film 200 e are formed of a SiO film, and include a strongSi—O bond so that the surfaces thereof are appropriately F-terminatedwithout etching and appropriately modified.

The processing procedures and processing conditions in the selectivegrowth when these pseudo catalyst films are used may be similar to theprocessing procedures and processing conditions of the aforementionedembodiments except that the pseudo catalyst film is formed on thesurface of the wafer 200 and step B is not performed. As describedabove, even when the Si film, the SiN film, the SiC film, the SiCN film,the SiRN film, the SiRC film, the SiRCN film, or the like is used as thepseudo catalyst, the same effects as those when the bare wafer is usedas the pseudo catalyst may be achieved.

Furthermore, as the pseudo catalyst, it may be possible to use, forexample, a gaseous pseudo catalyst, as well as the solid pseudo catalystsuch as the bare wafer, the Si plate, the Si chip, the Si piece, the Siblock, the Si-containing precoated film or the Si-containing pseudocatalyst film. As the gaseous pseudo catalyst, i.e., as the pseudocatalyst gas, it may be possible to use a gas for promoting thedecomposition of the F-containing gas to generate the F-containingradical from the F-containing gas by bringing it into contact with theF-containing gas. As the pseudo catalyst gas, specifically, it may bepossible to use, for example, at least one selected from the group of anO₂ gas, a N₂O gas, a NO₂ gas, a NO gas, a HF gas, an NH₃ gas, and ahydrogen (H₂) gas. The supply of these gases may be performedsimultaneously with the supply of the F-containing gas into the processchamber 201 using, for example, the nozzles 249 a and 249 c or the like.

In this case, at step C, the F-containing gas is supplied in anatmosphere in which the pseudo catalyst gas exists by simultaneouslysupplying the F-containing gas and the pseudo catalyst gas into theprocess chamber 201. At this time, the F-containing gas can be broughtinto contact with the pseudo catalyst gas, whereby the F-containingradical can be efficiently generated and the F-containing radicalefficiently generated in this way can be efficiently supplied to each ofthe base 200 b and the protective film 200 e. As a result, it becomespossible to appropriately modify the respective surfaces of the base 200b and the protective film 200 e. Furthermore, the F-containing gas andthe pseudo catalyst gas may be supplied into the process chamber 201alternately or intermittently as long as the F-containing gas and thepseudo catalyst gas are mixed in the process chamber 201.

The processing procedures and processing conditions in the selectivegrowth at this time may be similar to the processing procedures andprocessing conditions of the aforementioned embodiments except that theF-containing gas and the pseudo catalyst gas are supplied into theprocess chamber 201 and step B is not performed. As described above,even when the F-containing gas and the pseudo catalyst gas are supplied,the same effects as those when the bare wafer is used as the pseudocatalyst may be achieved. Furthermore, even when the gaseous pseudocatalyst is used, it is possible to lower the processing temperature atstep C and to effectively suppress the etching of the surface of thebase 200 a or the etching damage to the surface of the base 200 a atstep C, as in the case of using the solid pseudo catalyst.

Furthermore, the term “catalyst” refers to a substance in which itselfdoes not change before and after a chemical reaction, but which changesthe rate of reaction. The aforementioned substances exemplified as thepseudo catalysts have a catalytic action of promoting the generation ofF-containing radical, but some of these substances themselves changebefore and after a chemical reaction. For example, the NO gas has acatalytic action, but when reacting with the F-containing gas, a portionof the molecular structure may be decomposed so that itself may changebefore and after a chemical reaction. As described above, even if thesubstance itself changes before and after the chemical reaction, thesubstance that changes the rate of the reaction will be referred toherein as a “pseudo catalyst.”

In addition, for example, at step C, the generation of the F-containingradical from the F-containing gas may be promoted by activation(excitation) of the F-containing gas by plasma, heating, lightirradiation, or the like. Even in these cases, the same effects as thoseof the aforementioned embodiments may be achieved. Furthermore, at stepC, the generation of the F-containing radical in the process chamber 201may be promoted by activating the F-containing gas by plasma, heating,light irradiation, or the like, compared with the case where theF-containing gas is not activated by these, making it possible toincrease the amount of the F-containing radical to be generated. As aresult, it is possible to promote the modification of the respectivesurfaces of the base 200 b and the protective film 200 e, and toappropriately perform the selective formation of the SiN film on thesurface of the base 200 a at step C. Furthermore, it is also possible tolower the processing temperature at step C. Moreover, in the case ofusing plasma, it is desirable that a method of activating theF-containing gas by plasma in a remote plasma unit installed outside theprocess chamber 201 and then supplying it into the process chamber 201,i.e., a remote plasma method, be employed in order to suppress plasmadamage to the wafer 200 or any member in the process chamber 201.

In addition, in the aforementioned embodiments, there has been describedan example in which steps A, B, C, and D are sequentially performed onthe wafer 200 in which the base 200 a including the SiN film, the base200 b including the SiO film, and the base 200 c including the singlecrystalline Si are exposed on its surface, but the present disclosure isnot limited to the aforementioned embodiments. For example, instead ofthe base 200 a including the SiN film, a base including a SiCN film, asilicon boronitride film (SiBN film), a silicon borocarbonitride film(SiBCN film), or a silicon borocarbide film (SiBC film) may be exposedon the surface of the wafer 200. Furthermore, for example, instead ofthe base 200 b including the SiO film, a base including a siliconoxycarbide film (SiOC film), a silicon oxynitride film (SiON film), or asilicon oxycarbonitride film (SiOCN film) may be exposed. Moreover, forexample, instead of the base 200 c including the single crystalline Si,a base including an epitaxial silicon film (Epi-Si film), a polysiliconfilm (poly-Si film (polycrystalline Si film)), or an amorphous siliconfilm (a-Si film (non-crystalline Si film)) may be exposed. Furthermore,for example, in addition to the base 200 a including the SiN film, thebase 200 b including the SiO film, and the base 200 c including thesingle crystalline Si, a base including a conductive metallic thin filmsuch as a tungsten film (W film), a tungsten nitride film (WN film), ora titanium nitride film (TiN film) may be exposed. Also, instead of thebase 200 a including the SiN film, a base including the metallic thinfilm described above may be exposed. Even in these cases, the sameeffects as those of the aforementioned embodiments may be achieved. Thatis, it is possible to selectively form a film on the surface of the base200 a or the surface of the aforementioned metallic thin film whileavoiding film formation on the bases 200 b and 200 c.

Furthermore, in the aforementioned embodiments, there has been describedan example in which a monoaminosilane gas is used as theaminosilane-based gas at step B, but the present disclosure is notlimited to the aforementioned embodiments. For example, at step B, asthe aminosilane-based gas, a diaminosilane gas or a triaminosilane gasmay be used instead of the monoaminosilane gas. Even in these cases, thesame effects as those of the aforementioned embodiments may be achieved.However, at step B, as a gas having a smaller number of amino groupscontained in one molecule is used as the aminosilane-based gas, theadsorption density of Si on the respective surfaces of the base 200 band the protective film 200 e becomes higher, and at step C, the densityof SiF-terminations formed on the respective surfaces of the base 200 band the protective film 200 e becomes higher. As a result, at step D, itis possible to enhance the film formation inhibiting effect on therespective surfaces of the base 200 b and the protective film 200 e.From this viewpoint of point, it is particularly desirable to usemonoaminosilane including one amino group contained in one molecule asthe aminosilane-based gas.

Furthermore, in the aforementioned embodiments, there has been describedan example in which a cycle which non-simultaneously performs steps D1and D2 is implemented a predetermined number of times at step D, but thepresent disclosure is not limited to the aforementioned embodiments. Forexample, at step D, before starting the cycle which non-simultaneouslyperforms steps D1 and D2, a step of supplying an NH₃ gas for apredetermined period of time (NH₃ preflow) may be performed on the wafer200 in the process chamber 201, namely the wafer 200 after therespective surfaces of the base 200 b and the protective film 200 eamong the bases 200 a and 200 b and the protective film 200 e areselectively modified. Even in this case, since the F-terminationsexisting on the respective surfaces of the base 200 b and the protectivefilm 200 e are stably kept without being eliminated, the same effects asthose of the aforementioned embodiments may be achieved. Furthermore,the adsorption site on the surface of the base 200 a can be optimized,thereby improving the quality of the SiN film formed on the base 200 a.

Moreover, in the aforementioned embodiments, there has been described anexample in which the SiCl₄ gas is used as the precursor gas and the NH₃gas is used as the reaction gas at step D, but the present disclosure isnot limited to the aforementioned embodiments. For example, at step D,as the precursor gas, it may be possible to use, in addition to theSiCl₄ gas, a metal halide gas such as the aforementionedchlorosilane-based gas or titanium tetrachloride (TiCl₄) gas.Furthermore, for example, as the reaction gas, it may be possible touse, in addition to the N-containing gas such as an NH₃ gas, anO-containing gas such as an oxygen (O₂) gas, a N- and C-containing gassuch as a triethylamine ((C₂H₅)₃N, abbreviation: TEA) gas, aC-containing gas such as a propylene (C₃H₆) gas, or a boron(B)-containing gas such as a trichloroborane (BCl₃) gas. In addition, afilm such as a SiON film, a SiCN film, a SiOCN film, a SiOC film, a SiBNfilm, a SiBCN film, a TiN film, a titanium oxide nitride film (TiONfilm) or the like may be formed on the surface of the base 200 a whichis not modified, among the bases 200 a and 200 b and the protective film200 e, by the gas supply sequences illustrated below. The F-terminationsformed on the surfaces of the bases 200 b and 200 c are very stable, andtherefore, in these cases, i.e., when a gas containing an OH group suchas water vapor (H₂O gas) or the like is not used as the film-forminggas, the same effects as those of the aforementioned embodiments may beachieved.

O₂→SiH₃R→F₂→(SiCl₄→NH₃→O₂)×n⇒SiON

O₂→SiH₃R→F₂→(HCDS→C₃H₆→NH₃)×n⇒SiCN

O₂→SiH₃R→F₂→(HCDS→C₃H₆→NH₃→O₂)×n⇒SiOCN

O₂→SiH₃R→F₂→(HCDS→TEA→O₂)×n⇒SiOC(N)

O₂→SiH₃R→F₂→(DCS→BCl₃→NH₃)×n⇒SiBN

O₂→SiH₃R→F₂→(DCS→C₃H₆→BCl₃→NH₃)×n⇒SiBCN

O₂→SiH₃R→F₂→(TiCl₄→NH₃)×n⇒TiN

O₂→SiH₃R→F₂→(TiCl₄→NH₃→O₂)×n⇒TiON

Furthermore, in the aforementioned embodiments, there has been describedan example in which the DHF cleaning is performed on the wafer 200before performing the selective growth, but the present disclosure isnot limited to aforementioned embodiments. For example, after formingthe base 200 a, when the natural oxide films 200 d are not formed on thesurfaces of the bases 200 a and 200 c as in the case of performing theselective growth described above without exposing the bases 200 a and200 c to the atmosphere, the DHF cleaning may not be performed.

Recipes used in each processing may be prepared individually accordingto the processing contents and may be stored in the memory 121 c via atelecommunication line or the external memory 123. Moreover, at thestart of each processing, the CPU 121 a may properly select anappropriate recipe from the recipes stored in the memory 121 c accordingto the processing contents. Thus, it is possible for a single substrateprocessing apparatus to form films of different kinds, compositionratios, qualities and film thicknesses with enhanced reproducibility. Inaddition, it is possible to reduce an operator's burden and to quicklystart each processing while avoiding an operation error.

The recipes mentioned above are not limited to newly-prepared ones butmay be prepared by, for example, modifying the existing recipes alreadyinstalled in the substrate processing apparatus. When modifying therecipes, the modified recipes may be installed in the substrateprocessing apparatus via a telecommunication line or a recording mediumstoring the recipes. In addition, the existing recipes already installedin the substrate processing apparatus may be directly modified byoperating the input/output device 122 of the existing substrateprocessing apparatus.

In the aforementioned embodiments, there has been described an examplein which films are formed using a batch-type substrate processingapparatus capable of processing a plurality of substrates at a time. Thepresent disclosure is not limited to the aforementioned embodiments butmay be appropriately applied to, e.g., a case where films are formedusing a single-wafer-type substrate processing apparatus capable ofprocessing a single substrate or several substrates at a time. Inaddition, in the aforementioned embodiments, there have been describedexamples in which films are formed using the substrate processingapparatus provided with a hot-wall-type process furnace. The presentdisclosure is not limited to the aforementioned embodiments but may beappropriately applied to a case where films are formed using a substrateprocessing apparatus provided with a cold-wall-type process furnace.

In the case of using these substrate processing apparatuses, eachprocessing may be performed by the processing procedures and processingconditions similar to those of the aforementioned embodiments. Effectssimilar to those of the aforementioned embodiments may be achieved.

The embodiments described above may be appropriately combined with oneanother. The processing procedures and processing conditions at thistime may be similar to, for example, the processing procedures andprocessing conditions of the aforementioned embodiments.

Examples

A plurality of wafers each including a SiN film (first base), a SiO film(second base), and a single crystalline Si (third base) exposed on itssurface were prepared. The surface of each wafer was cleaned using a DHFaqueous solution to remove natural oxide films formed on the surfaces ofthe SiN film and the single crystalline Si in each wafer. Thereafter, aprocess of forming a SiN film on each wafer using the substrateprocessing apparatus illustrated in FIG. 1 was performed to produce twoevaluation samples (samples 1 and 2).

When producing sample 1 (example), steps A to D in the aforementionedembodiments were each performed. The processing conditions at steps A toD were set to predetermined conditions which fall within the processingcondition range described in the aforementioned embodiments.

When producing sample 2 (comparative example), step A in theaforementioned embodiments was not performed, and steps B to D were eachperformed. The processing conditions at each of steps B to D were setsimilar to the processing conditions at each of steps B to D whenproducing sample 1.

As results of observing both a SEM image and a TEM image of crosssections of samples 1 and 2, it could be confirmed that in sample 1 inwhich step A was performed, the surface of the third base was notdamaged by etching. On the other hand, in sample 2 in which step A wasnot performed, it was confirmed that the surface of the third base wasdamaged by etching. Furthermore, it was confirmed that in any of samples1 and 2, the SiN film could be selectively formed on the surface of thefirst base.

According to the present disclosure in some embodiments, it is possibleto enhance a selectivity in the selective growth described above whilesuppressing damage to a surface of a base.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the disclosures. Indeed, the embodiments described herein maybe embodied in a variety of other forms. Furthermore, various omissions,substitutions and changes in the form of the embodiments describedherein may be made without departing from the spirit of the disclosures.The accompanying claims and their equivalents are intended to cover suchforms or modifications as would fall within the scope and spirit of thedisclosures.

What is claimed is:
 1. A method of manufacturing a semiconductor device,comprising: (a) forming a protective film on a surface of a third baseby supplying a processing gas to a substrate in which a first basecontaining no oxygen, a second base containing oxygen, and the thirdbase containing no oxygen and no nitrogen are exposed on a surface ofthe substrate; (b) modifying a surface of the second base to befluorine-terminated by supplying a fluorine-containing gas to thesubstrate after the protective film is formed on the surface of thethird base; and (c) selectively forming a film on a surface of the firstbase by supplying a film-forming gas to the substrate after the surfaceof the second base is modified.
 2. The method according to claim 1,wherein the protective film contains oxygen.
 3. The method according toclaim 2, wherein in (a), the protective film is formed by supplying anoxygen-containing gas as the processing gas to oxidize the surface ofthe third base.
 4. The method according to claim 3, wherein in (a), thesurface of the third base is oxidized by dry oxidation.
 5. The methodaccording to claim 3, wherein in (a), the surface of the third base isoxidized under a pressure lower than an atmospheric pressure.
 6. Themethod according to claim 3, wherein in (a), the surface of the thirdbase is oxidized under a condition in which the surface of the firstbase is not oxidized.
 7. The method according to claim 2, wherein in(b), a surface of the protective film is modified to befluorine-terminated.
 8. The method according to claim 1, wherein in (b),the surface of the second base is modified to be fluorine-terminatedwithout etching.
 9. The method according to claim 1, wherein in (b), thefluorine-containing gas is supplied to the substrate in an atmosphere inwhich silicon exists.
 10. The method according to claim 1, wherein in(b), the surface of the second base is modified to befluorine-terminated by sequentially performing: (b1) supplying anaminosilane-based gas to the substrate; and (b2) supplying thefluorine-containing gas to the substrate.
 11. The method according toclaim 10, wherein in (b1), silicon contained in the aminosilane-basedgas is adsorbed on the surface of the second base, and wherein in (b2),the surface of the second base is fluorine-terminated by reacting thesilicon adsorbed on the surface of the second base with thefluorine-containing gas.
 12. The method according to claim 11, whereinin (b1), the silicon contained in the aminosilane-based gas is adsorbedon a surface of the protective film, and wherein in (b2), the surface ofthe protective film is fluorine-terminated by reacting the siliconadsorbed on the surface of the protective film with thefluorine-containing gas.
 13. The method according to claim 1, furthercomprising: (d) removing a natural oxide film formed on the surface ofthe substrate before performing (a).
 14. The method according to claim13, wherein in (d), a material of the first base is exposed.
 15. Themethod according to claim 14, wherein in (d), a material of the thirdbase is exposed.
 16. The method according to claim 1, wherein the firstbase includes a nitride film, the second base includes an oxide film,and the third base includes a semiconductor material.
 17. The methodaccording to claim 1, wherein the first base contains silicon andnitrogen, the second base contains silicon and oxygen, and the thirdbase contains silicon.
 18. The method according to claim 1, wherein thefirst base includes a silicon nitride film, the second base includes asilicon oxide film, and the third base includes a single crystallinesilicon, an epitaxial silicon film, a polycrystalline silicon film, oran amorphous silicon film.
 19. A substrate processing apparatus,comprising: a process chamber in which a substrate is processed; aprocessing gas supply system configured to supply a processing gas tothe substrate in the process chamber; a fluorine-containing gas supplysystem configured to supply a fluorine-containing gas to the substratein the process chamber; a film-forming gas supply system configured tosupply a film-forming gas to the substrate in the process chamber; and acontroller configured to be capable of controlling the processing gassupply system, the fluorine-containing gas supply system, and thefilm-forming gas supply system so as to perform a process in the processchamber, the process comprising: (a) forming a protective film on asurface of a third base by supplying the processing gas to the substratein which a first base containing no oxygen, a second base containingoxygen, and the third base containing no oxygen and no nitrogen areexposed on a surface of the substrate; (b) modifying a surface of thesecond base to be fluorine-terminated by supplying thefluorine-containing gas to the substrate after the protective film isformed on the surface of the third base; and (c) selectively forming afilm on a surface of the first base by supplying the film-forming gas tothe substrate after the surface of the second base is modified.
 20. Anon-transitory computer-readable recording medium storing a program thatcauses, by a computer, a substrate processing apparatus to perform aprocess in a process chamber of the substrate processing apparatus, theprocess comprising: (a) forming a protective film on a surface of athird base by supplying a processing gas to a substrate in which a firstbase containing no oxygen, a second base containing oxygen, and thethird base containing no oxygen and no nitrogen are exposed on a surfaceof the substrate; (b) modifying a surface of the second base to befluorine-terminated by supplying a fluorine-containing gas to thesubstrate after the protective film is formed on the surface of thethird base; and (c) selectively forming a film on a surface of the firstbase by supplying a film-forming gas to the substrate after the surfaceof the second base is modified.